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Finding the Fourth Proportional to 86.77, 129.66 and 66.09

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Solution

The fourth proportional to 86.77, 129.66 and 66.09 is: 98.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.77 : 129.66 = 66.09 : x
  2. Step 2: Convert to fraction form
    86.77/129.66 = 66.09/x
  3. Step 3: Cross multiply
    86.77x = 129.66 × 66.09
  4. Step 4: Simplify right side
    86.77x = 8,569.69
  5. Step 5: Solve for x
    x = 8,569.69/86.77
  6. Step 6: Final answer
    x = 98.76

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.